Presbyopia is an age related condition that makes it difficult for people to see objects up close. As people age, the crystalline lens within the eye hardens and loses the elasticity that is required to focus on close objects. Presbyopia may seem to occur suddenly, but the actual loss of flexibility takes place over a number of years. Presbyopia usually becomes noticeable in the early to mid-forties. This condition is a natural part of the eye's aging process. It is not a disease and cannot be prevented. Presbyopia will affect everyone, including people who wear glasses to correct distance vision, astigmatism, or a combination of both. Presbyopia is overcome by the use of corrective reading glasses and by other means including bifocal lenses, magnifiers, contact lenses and controversial corrective eye surgery.
Various designs for reading glasses are known. Conventional reading glasses comprise plastic or glass corrective lenses secured within plastic, or metal rim-type eyeglass frames. The frames typically have a pair of ear retainers hingedly connected to either end, so that the reading glasses can be worn on the bridge of the nose and secured by the ears of the wearer. While such conventional designs for reading glasses work well when properly prescribed and worn, because reading glasses are used to supplement the use of distance vision glasses or contact lenses, they are often forgotten or left behind because they are inconvenient to carry.
While bifocals have been developed to address the problem of forgetting or leaving behind reading glasses, many people find bifocals disorienting, particularly when viewing at an angle where the reading portion of the lens meets the distance portion of the lens. Consequently, many people choose not to wear bifocals and instead keep a separate pair of reading glasses.
Magnifiers may also be used to address presbyopia but they have a field of view which is limited by the size of the magnifier and the distance held from the reading material. Their size and their long handles make them bulky and cumbersome to carry. Finally, as magnifiers do not provide binocular vision, a reader is sometimes required to close one eye in order to achieve viewing clarity.
Contact lenses and surgical techniques are also available to correct presbyopia. However, contact lenses have their drawbacks, as will be appreciated by people who have worn them, and surgical techniques are expensive and still being perfected.
As a result, situations often arise where reading glasses are required but are not readily at hand. Some examples of these frustrating situations include: being in a candlelit restaurant unable to make out the menu entrees; standing in front of the medicine cabinet unable to read prescription dosage instructions; locating a map in the glove compartment but unable to read the small print; searching for a number in the telephone book but unable to read the listings, etc. Thus, there is a need for increased availability of reading glasses so that they are readily available when and where they are required to provide short-term vision assistance for reading.
A major limiting factor in determining the level of availability is cost. Conventional reading glass designs typically require many manufacturing steps and involve the assembly of many parts resulting in a fairly high per unit cost. Thus, the cost of purchasing multiple units of conventional reading glasses for placement in various convenient locations may be prohibitively expensive.
Designs have been proposed which attempt to lower the per unit cost of reading glasses. For example, an integral design for reading glasses is disclosed in U.S. Pat. No. 5,559,566 (Hansman). However, the reading glasses in Hansman '566 still require the assembly of spring clamps at either end of the integral front piece design for connection of a necklace support. In addition, the reading glasses disclosed in Hansman '566 are designed to be supported on the nose of the wearer and do not provide a handle for hand-held operation. Furthermore, according to the Hansman '566 disclosure, at column 2, lines 29 and 30, the lens portion of the design is made in strengths between 1.00 through 4.00 in quarter increments. Thus, the Hansman '566 design contemplates customized prescriptions for use by one person. While a customized prescription is desirable for long term reading, it is not strictly necessary for short-term reading assistance. The need to manufacture lenses of different strengths for different wearers may tend to increase manufacturing costs, since different tools and/or tool adjustments will be required in order to produce lenses having a plurality of different strengths. For example, providing lens strengths between 1.00 through 4.00 (in quarter increments) will require thirteen different versions of the product. Having many different versions of a product will also introduce various logistics problems and issues with product manufacturing and marketing which would otherwise be avoided. Furthermore, it can also be noted that the Hansman '566 design is not planar, and hence is not readily suited to storage inside, say, a telephone directory or restaurant menu.
The present invention is designed to overcome the drawbacks in the prior art, as identified above.